Work holder for welding



Sept. 11`, 1928.

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w. H. D'ARDENNE ETAL woRx HOLDER Foa WELDING Filed Sept. 12, 1925 12 Sheets-Sheet 1l Patented Sept. l1, 1928.

UNITED STATES PATENT OFFICE.'

WALTER B'. DARCDENNE, 0F LAWNDALE, J'. OLIN LANDIS, OF FOX GHASE, LEWIS H. GHRISTENSEN, OF PHILADELPHIA,

v MANUFACTURING COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

WORK HOLDER FOR WELDING.

Application led September 12, 1925. Serial No. 55,934.4

This inventionrelates to automatic welding, and more particularly relates to the automatic welding of axle housings, including improvements in method and in apparatus therefor.

Axle housings for the rear axles and difjferential gearing'of automobiles are well 'A known, and conventionally comprise two longitudinal sheet m'etal halves seam-welded together.A Sometimes bearing tubes are secured within the housing arms. Heretofore this welding has been accomplished by hand, by which is meant that the worker uses a hand welding tool; S0 far as applicants are aware, the welding of axle housings has not been accomplished heretofore in a satisfactory manner by means of a mechanically directed welding tool, although there are known machines for mechanically directing welding tools to weld together iin-stamped plates of light gauge metal, as in lthe manufacture `of metal tanks and containers. To secure a satisfactory seam weld by a mechanically directed tool the parts', to be welded together must be )held together tightly or the welding will be faulty. Also,

variance in the width of the seam islikely t0V result in faulty welding, whic'hwould be -apt to be insufficient at the wider portions, or n overmuch at the close portions, since the speed of movement ftlie mechanically directed tool would be constant. Axle housing sections-are formed of heavy sheet metal stamped to shape, and the edges are apt to be slightly vuneven and rough, and possibly one reason for `the failure hereto/fore' to weld them by automatic machines has -been the failure to bring and hold the. sections togetlier properly: Another source of. inter- 40 ference to proper and even seam welding arises from localmagnetic ieldsestablished in thework during the welding operation, these' nag'netie forces deflecting the arc in variousdirections, sometimes ,entirely away from the work, and repelling 'the iux fromV the seam. -with -the result that the weldis faulty. c These 'magnetic fields are C. more evident and stronger where heaviersinetal is worked upon. Therefore, an arrangement which would be satisfactory for light metal would be apt tobe entirely inoperativejwhen l' used for heavier metal, such as used for axle housings. This may be another reason vfor the failure heretofore to weld axle housings by automatic machines. The shape of the work may also have some influence on these local magnetic fields.

Applicants have invented, constructed and used a machine for welding axle housings automatically, that is, by means of a mechanically directed welding tooland this is a principal obj ect of this invention. By means of such a machine axle housings may be welded very quickly and in quantities at very low cost, requiring very little labor and a minimum of space.

The welding head which delivers the welding wirekand the automatic m'eans for PENNSYLVANIA, ASSIGNORS- TO HEINTZ ditions of the arc, were not invented by us,

but are available "in the open market, and

thus replacement of these parts is less expensive than if special construction were required. We have, however, invented mechanism wherebythe welding head-is mechani-V cally and automatically directed so as to weld an axle housing in a most satisfactory manner, and to produce even and good welding, without faults, along 'the seam, and without requiring special treatment of the edges of the housing sections to eliminate roughnessand irregularities, and this is an other object of our invention.

A ,further object of our invention is to vprovide .an improved jig which automatically, under 4the direction of the operator,

housing very rigidly and tightlytogether, and presents them to the automatic Welding apparatusin la way which is conducive to the best of welding, and avoids faulty weldpositions and holds two halves of an axlev ing due to improper placement and holding 7 of" the housing sections, and prevents deformation of the housingduringwelding.

Another object ofour invention is to providel for th^ easy removal of the jig from the welding mechanism to permitthe easy substitution of another jig adapted to an axle housing of a differ-lent type "or shape, thus providing a machine which will operate on different types and shapes o f housings with the same welding apparatus.4

showers of sparks,and another object of our '.During welding there are scattered about l .invention is to provide a construction whereaxle housings of dili'erent types may be welded in quantities, very quickly; and at the same timeis reliable, producing excellent Welds uniformly, and is convenient and simple to operate.

Other objects of this invention will be in part obvious and in part pointed out hereinafter.

' In accordance with our invention, we provide a jig provided with means for aligning the two axle housing sections with each other, for clamping and holding them tightly together, and for presenting them to the welding apparatus for welding, and preventing distortion of the housing. These means are operated pneumatically and include a system of plungers and clamps, which engage the two axle housing sections when placed on the jig, and there is a' single control for actuating these means in a 'predetermined The jig preferably is removablese i1ience bo '-ly from the welding apparatus to permit substitution of another jig designed for aV different type or shape'of housing, the same Welding apparatus beingadapted to various types and shapes of housings.

The welding apparatus includes two traveling welding heads, each provided with means for dispensing the wire in accordance .f with arc conditions during the welding.

This type ofl head isy conventional. YEach head is mechanically movable transversely ofsthe housing, into welding position thereover, 'and movable away from the housing to permit a welded housing tol be lifted from l or turned over in the j ig without obstruction.

EachV head is also mechanically movable longitudinally along the housing,.oneover each end thereof, and each head welding the fseam between one end and the central portion of the housing. The heads preferably move in unison in the same directions, but each head may be caused'to move independently of the other. Automatic stops are provided to stop the travel when the end of the seam is reached. Automatic' means Vare also provided for stopping the travel whenever the welding are is extinguished. Means are also provided for returning the'heagls to initial position. The machine is so arranged In order that a clearer understanding of our invention may be had, attention Vis hereby directed to the accompanying drawings,

forming a part of this application and illustrating certain possible embodiments of our invention. Referring' to the drawings, Fig. 1 is a front elevation of the entire inachine; Fig. 2 is a top view of the same; Fig. 3 is an end elevation of the same; Fig; is a sectional view on the line 4-4 of ig. 2; Fig. 5 is a sectional detail of the welding head adjusting mechanism; Fig. 6 is a rear elevation of a portion of the machine; Fig. 7 is a sectional det-ail on the line 7 7 of Fig. 6; Fig. 8 .is a top view of the fragment of the machine, partly broken away; Fig. 9 is a sectional view on theuline9f-9 of Figs. 4 and 8; Fig. 10 is a sectional elevational view of the jig taken on the line 10-10 of Fig. 1; Fig. 11 is a longitudinal sectional view of a fragment of the jig, and is taken on the line 11-11 of Fig. 2; Fig. 12 is an-end elevation of the plunger and slide shown in Fig. 1l; Fig. 13 is a sectionalview taken on the line 13-13 of Fig. 11; Fig. 14 is a fragmentary top vview of the central portion of the jig unit with certain portions broken away, as on the line 14--14 of Fig. 15; Fig. 15 is a front elevation of the same partially broken away;

Fig. 16 is a horizontal sectional view of master valve, taken on the lines 16-16 of Figs. 17 and 18,; Figs. 17 and 18 are sectional views respectively on the lines 174-417 and 18-18 of Fig."16; Figs. 19 to 23 inclusive are diagrammatical view s cshowing the housing and. the successive movements of the work engaging devices with respect thereto Fig. 24 is a top view of an lunvvelded axle housing; Fig. 25 is av longitudinalsectional view on the line 25-25 of Fig. 24; and Figs. 26, 27 and 28 are cross sectional views respectively on the Vlines, 26-26,

27-27 and 28-28 of Fig. 24. Similar reference characters refer. -to similar parts throughout the several views of the drawinos.

teferring to the drawings,l the s'u pport for the welding apparatus includes a p uml-"121 Aity of standards40, to which is attached acasting 41 which extends the full lengthof the machine and forms an inverted channel having side walls 42 and 43With inwardlyextending tracks 44 and45 atA their lower edges.

f The welding apparatus in the,v embodiment shown comprises two-complete-units. Each unitlis mounted for longitudinal movement- 'along this table. To this end for each unit Lasagna wardly from plate 49 and between the runways 44 and 45 are walls 51 and 52 on which are formed two pairs of journals 53 and 54. In each pair of journals there is rotatably mounted an axle, 55 and 56, the ends of which are attached to rollers 38 and 39, which roll on the tracks 44 and 45. 4One,

vof these axles, 56, has a gear 57 keyed thereto. In mesh with gear 57 is another gear 58, which is pinned to a shaft 59. On one L side of gear 58 shaft 59 is .journaled in -a bearing 60 formed integral with plate 49 beneath one of the journals 54,"and onthe other side of gear 58 shaft 59extends into a sleeve 61, which is pinned, as at 62, to another shaft 63, which is in axial alignment with-shaft 59. Shaft 63 is journaled in a bearing 64 formed integral with plate 49 beneath the other bearing 54. From bearing 64 shaft 63 extends through a bearing 65 formed on member 49, and at its end carries a worm wheelV 66. A. collar 67 interposed between the bearing 65 and the. hubI of the worm Wheel prevents inward movementof the shaft 63, and the abutment of sleeve 61 against bearing 64 prevents outward movement of this shaft. The hub of gear 58 has clutch jaws 70 coacting with clutch jaws 71 on sleeve 61, so that when thisclutch is engaged'gear 58 will rotate with shaft 63. This clutch is disengagedv by sliding gear 58 and its shaft 59 away from the sleeve 61. On' the other end of shaft 59 is secured a sleeve 72, which has clutch jaw's 73, coaeting with clutch jaws 74 on a sleeve 75, which ispinned to a stub shafto76, mounted for rotation in a journal 77 formed on side wall 47. On the outer end of shaft 76 is carried a gear 78, with whichmeshes a pinion 79011 a stub shaft 81 carried on the wall 47 and rotatable' by means of hand wheel 80. When gear 58 is moved `to the left (Fig. 4), its connection with. shaft 63 is broken, and it becomes connected with shaft 76 through the engagement of clutch jaws 73 and 74. Thus, when the parts are in this position, the welding unit supporting member 46 may be moved longitudinally/.011 the stationary support 41 by rotating hand wheel 80.

The connection between gear 58 and shaft,

63 permits similar movement by power means through an enclosed shaft 82 which is carried on brackets 83 mounted on wall 48, the shaft at one end having a worm 84 in mesh with worm wheel 66 and having atits other end a worm wheel 85 which meshes witln a worm 86 driven by a motor 87 through suitable gearing 88. The motor and gearing are mounted on the movable support 46. n

- One of the features of this` invention is the protection of the rollers and their run-- Ways from contact withjsparks emitted during welding operations, and also V'from dustY and dirt, thus insuring even and unobstructed movement of the welding units along the stationary table. 'lo aid in maintaining smooth and even movement, thetracks are machined and well lubricated. The importance of maintaining unobstructed move' ment of each welding unit will become apparent hereinafter.

Bolted to the top of movable member 46 are Castings '90, which carry rollers 91.v Restin on rollers 91 is the carriage 92, having downwardly-presented runways or tracks 93. Carriage 92 carries the welding apparatus .consisting of a wire-reel l94 and a welding-head which in its entirety is designated 95. Both the reel and -thc weldingheadare insulated from the carriage 92. Reel 94-is supported by brackets 96, which rest on insulation block 97 and are bolted to the carriage 92 as at 98, the bolts being insulated from the brackets by suitable insulating bushing 99 and washer 100.

Each 4welding-head 95 is broadly conventional, comprising a motor 101, which, through suitable reductionI gearing contained in housing 102, drives "the wire feed rollers 103.' The 'wire 104 from the reel 94 `is engaged between these feed rollers 103 and extends through guide sleeve 105 into position for performing the welding operations. Preferably vthe Welding-head is mounted so as to be adjustable in a limited degree on the carriage 92. It'also must be insulated therefrom. The various items of the welding head are mounted on acasting 107,'which is rigidly carried on the shaft 106. Shaft 106 is rotatably mounted in bearings 108, provided on a plate 109, which is bolted, as at 110, to the carriage 92. This plate 109 is insulated from the ear )Ulu riage 92 by the interposed insulation block l 111v and insulating bushings 112 and washers 113. -Shaft 106 has worm teeth 114, and on the bearing member 108 is carriedv a small VWorm 115 in` mesh with teeth 114. Worm 115 is rotatable by means of a,

knurled knob 116, whereby 'the shaft 106e.,

may be rotated relatively to the carriage` 92 with the pivot point at this shaft. he purpose of permitting` this adjustment to provide means for bringing the end of the welding wire into` exactly the proper locaftion for performing the welding operations.

Pneumatic means are provided for moving Ithe carriage 92 and all vthe apparatus carried Athereby erosswise of the longitudinally mov- -able frame 46. Obviously, manualmeans may be employed for effecting this movecentral 'secured to the cross-carriage 92.

the end of the welding stroke and for automatically returning the carriage to initial welding position. -To this end anangle iron is secured to the rear of the two stand-y ards.40, and slidably adjustable along this angle iron are two pair of blocks 131, one pair for each welding unit. Each block straddles a flange of the angle iron and may y.be locked in' place by set screwl 132. On each block is a pivoted pawl 133 anda stop pin 134. Each carriage 46 carries. a reversing switch on a bracket 136, and the switch has a forked operating member 137, which, when it approaches a block 131 re- -ceives the pa'wl 133 and by reason of stop pin 134 throws the switch, but on reverse movement of the carriage the pawl is'l free and the switch is not, thrown. At'the end of the welding movement lthe switch is "thrown to reverse the circuit to the motor 87,

and when the carriage has returned to initial position the switch is set to pass the current in the opposite direction to permit starting of motor 87 by the operator, or to start the motor automatically to causev forward travel of the carriages, as desired. We shall now take up the ig unit. This comprises two lower beams 1 0 supported on casters 141, preferably arranged to roll in channel tracks 142 located. on the floor. Bolted to and extending between and beyond the beams is a frame casting 143 to which the jig parts are secured. The ends of this frame are detachably securedV to the Standards 40 by angle irons 144, when weld-ving is tobe done. Centrally on the-top of frame 143 is an annular pedestal 145 on which the housing sections 146 rest. Extending upwardly through this ring and between the'V housings, at their enlarged ortions are two anvilv blocks vwhich shdably-rest on abrid eportion 147 -of frame 143 and against gui e bars 148 and 149. Bar 148 isfdetachably secured to frame 143 over the bridge 147 bybolts `150. \Bar 1491is detachably secured to frame 143 over bridge '/1'47 byboltsr151 which'seat in slots- 152 in-' this 'bar. Bars -148 .and`149 'engage each other along an incline 153, s'o that by adjusting bar y149 longitudinally with respect to -bar 148 this inclined surfacfciontact will cause'the distance between the guide sur-.- faces of .theI bars .to be increased-"or @11minished. This permits adjustment to compen- 1,esa,7ea l sate for the wearing down of the guiding surfaces. These guiding surfaces are undercut and coact with similar surfaces on the anvils, as at 154. By reason of the bars 148 and 149 overhanging ortions of the anvils, the latter cannot be dlsplaced upwardly unless the bars are removed.

The anvil blocks 155 extend the entire height of the housings and are semi-circular, having a curved peripheral surface, as at 156, which fits each housing section at its curved central portion. each block is milled out to provi de oppositely tapering wedge surfaces 1,57 and 158 with which coact a pair of moving wedges 159 and 160, there being shoulders 161 `on the anvils to support the wedges. Each wedge has a plunger head 162 which fits snugly into the inner end of a bearing tube 163 (which is part ofthe housing) when the wedges are i there is a pneumatic cylinder 165, mounted on the frame 143, having a piston rod 166 extending througha bearing 167 of annular casting 168 on which rests pedestal ring 145. Each rod 166 has toward its outer end a sleeve 169 abutting wedge 159 or 160, at a shoulder- 170, and has a head 171 seated in a recess 172-in the wedge, 'so'that movement of the wedges follows movement of the rods 166 in either direction. Thus it will be seen that when the rods 166' are moved outwardly the wedges cause the anvil blocks 155 to expand tightly against the housing sections, and also will cause the plunger heads 162 of the wedges to enter the bearing tubes 163.

l These plunger heads thereby place'and maintainthe engaged ends of the bearing tubes in accurate alignment. When the rods 166 are moved toward the center, the wedges and their plunger heads leave the tubes and the anvil blocks are released for collapsing and withdrawal from engagement with the housing sections. These anvil blocks then may be collapsed by strong opposed springs 173 which encrcle a rod 174 extendin through'4 both anvil blocks, each spring 173 eing collapsed between a nut 175 on an end of the rod and the body of the block. Each wedge may beprovided with a projection-17 6 which may be 'knocked or hammeredl to aid in:

eifecting'the release of the wedge if such aid becomes' necessary. v To clampth'e housing sections Vtogether at their centers there are four clamping devices device there is a bracket 181 bolted to frame i143 and Ito member1168, 4the bracket having two parallel projections or walls 182. At the upper ends these projections support a shaft 4183 on which is pivoted a clamp 184. The

engaging face of the clamp, is curved to con- -form to'the housing surface .to be'engaged The inner side of i taining a double` acting piston which operates a rod 188, connected to a block 186.

-Each cylinder 187 may be secured to a bracket 181. Eachv clamp may be protected by a suitable shield 189.

To further position and clamp the housing sections there v'are provided two pair of clamping devices 190, each pair adapted to l' engage and clamp togetherbjrom opposite sides the two halves of one arm of the hous': ing. rlhese clamping devices are similar to the clamping `devices 1804 heretofore described. The operating cylinders 191 for these clamps are bolted to the main frame 143.

Adjacent each end of the housing is'- a carriage 192 slidable on a pedestal 193 which is secured to frame 143. At the front of each carriage 192 is a plunger which tits into the outer end ot the housing and enters a bearing tube 163 to place the housing ends and the tubes in accurate alignment. Each plunger has a cylindrical body 194, to the end of which is secured a plug 195 which fits in the end of the bearing tube. The body has an inclined longitudinal slot 196 and a wedge' 197, preferably of copper, slidable in the slot, and preferably being locked therein by a dovetailed engagement as at 198. If this Wedge were not pre-:ent the body 194, by

reason of expansion under theheat of Weld,

ing, would be apt to be'wedgcd sotightly in the housing that its immediate removal would be diiiicult. The Wedge device 197 permits easy removal of the plunger even While hot, and also provides a taper surface for the initial withdrawal movement of the plunger. When the plunger is taken into the housing the projection 1 99 on-the Wedge is engaged by the bearing tube and causesthe wedge to be moved home.. Each carriage 192 v is moved in both Vdirections by means of apiston rod 200 connected to` a piston in a cylinder 201, which is secured to pedestal 193. Each piston rod 200 carries a block 203 Which-has some lost motion between plunger body 194 and a shoulder 204 on carriage 192. Thus, on return movement, vthe block 203 ditional force ot momentum and impact is created to initiate movement .of plunger from the housing after welding.4 Preferably a cover 202 isvprovided :to protect the piston rod 200 from Welding sparks-and dirt. Each carriage 192 has a dov'etail sliding' engagement on pedestal 193-to prevent displacement of the carriage and to maintain the plunger 194 in proper and accurate alignment.

As before stated, the varioushousing positioning and' ho1ding devices are operated neumatically. Preferably all are operated 'om a single control. The control shown comprises a valve A210,"consisting of a housing 211 bolted to the frame 143, and a valve cone 212 Within the housing. The cone has four semicircularv passages, one,r214, to let air into the jig cylinders to actuate the work engaging'devices into engagement with the Work, another, 213, to allow this air to eX- haust, another, 216, to let air intothe cylinders to take the pistons into releasing position, and the fourth passage, 215, to allow this air to exhaust. The housing has au air intake 218, through pipes 310 and 301,l from a suitable source of compressed air, into passage 214, an outlet 217 from passage 216, and an outlet 219 from assage 215. The cone 212 isV rotatably held. the casing by a cover or yoke'221 and abolt 222, and is rotatable back and forth for about 140 213, a compressed air intake 220 into passage degrees -by means of a single operating handle 223. Passages 213 a11d214are opposite each other, as are also the passagesV 215 and 216. Valls 224 and 225 on thecone separate passages 213 and'214ai1d .walls 226 and 227 on the cone separate passages 215 and 216. When the handle 223 is at the extreme right (see Figs'fl'( and `18) the outlet 217 is open into passage 213, which in this position communicates with air ports 228, 229, 230, 231 and 332 through the housing. Passage 214'which'communicates with inlet port 218 hasno outlet in this position of the valve. At 'the same time the inlet port 220 is open into passage216 and air ports 233, 234, 235, 236 and237 communicate with this passage. In this position 215 communicateonly with outlet 219. In the present embodiment ports A[232 and 237 are not used and, therefore, are closed by suitable plugs 238 and 239. [Pipes .240 connect portv v 228 to the ports 241 of both wedge operating cylinders 165. Pipes 242 lead from port 229 to ports 243 each of the end plunger operating cylinders 201. Pipes lead from port 230to the ports 245v Aof all four v central clamp operating cylinders 187. Pipes 4246 llead from port 231- to thel ports 247 in the arm clamp operating cylinders 191. Pipes 248 lead from port 233 to ports 249 in cylinders 165. VPipes 250 lead from ort 234 to ports 251 inl cylinders' 201. knocks against the shoulder 204 and an ad-` ig 223 ismoved tothe left from the aforef mentioned position, then, byreason of'Wall 225, each p0rt228,` 229, 230, 231 and 332 I is taken out of communication with passage 213 and outlet 217 and `brought into communication with passage 214 and inlet 218, in the sequence stated. At the same time, by reason of wall 227, eachport 233,

234, 235,236 V'and 237 is taken out of coinmunication with passage 216 and inlet 220 and brought into communication with passage 215 and outlet 219. The former se- A valve handle is moved to the left, as indiv andpipe, 240 enters -165 and -at the same time air exhausts from cated by thearrow in Figs. 17 and 18, the following sequence transpires. Compressed air through port 218, passage 214, port 22S ports 241 of cylinders cylinders 165 through ports 249, line 248, port 233, passage 215 and valve exhaust port 219. This actuates wedges 159 and 160 to ,spread anvil blocks 155 and to take the plunger heads 162 into bearing tubes V`163, see Fig. 20. Then compressed air through ort 229, pipe 242 enters ports 243 Y of cylin ers 201 and at the same tinie'air exhausts through cylinder ports 251, pipe 250, valve port 234, passage 215 and vexhaust `219. This takesp'end plungers 194 into --engagement with the outer ends of the axle housing arms and ,bearing tubes 163,

Y see Fig. 21. Then compressed air through port 230 and pipes 244 enters ports 245 of cylinders 187, and at the\same time air exhausts through ports 253 of these'cylinders, pipes 252, valve port 235, passage 21'5 and exhaust 219. This engages the diagonal central clamp 180 with the work, see Fig. 22. Finally, compressed air through port 231 and pipe 246 enters ports 247 of cylinders 191, and at tl'e same time air exhausts from cylinder ports 255, through pipes 254, valve port- 236, passage 215 and exhaust 219. This takes the arm clamps 190 in engagement with the work, see Fig. 23.. The housing gections are thus placed in accurate alignment and are held tightly clamped together'aid held against distortion bythe heat of welding. The housing is also in accurate position on the jig, and the lines to be weldedv are placed in an exact predeter- 'inined location so that the welding wire will align therewith accurately, Without requiring adjustment of the weldino machineY or jig for each housing to be welded."

To release the work, the valve handle is -moved from left to right (Figs. 17 and 18),

that is, counterclockwise. Air will now leave the cylinder -ports through which air enteredduring -the engaging operation and compressed air will enter the cylinder ports through which air was exhausted, following the engaging movement of the valve handle. The devices, of course, will be actuated in the reverse sequence, as movement of valve handle is reversed.

After the housing has been engaged onl the jig in the manner stated, the operator now operates the valve 30C to cause air froma supply coming from pipes 301 and passing through pipes 302 into the port 303 of cylinders 120to bring the welding units foi'- wardly into posit-ion over the housing. If more accurate adjustment is necessary, the operator accomplishes this by turning knobs 116. After adjustment for the first housing,` adjustment for succeeding housings is required very seldom. Having .obtained proper adjustment of the welding-wire over the seams t-o b'e welded, the operator actuates .the switches 304 to start the motors 87, which' move the welding units along the .housing Sli scams to be welded, and the seams are welded automatically by the apparatus heretofoie described. Th`e operation of thev welding head is well known and, therefore, a de! tailed description thereof is believed to -be unnecessary. Should the operator wish to stop the travel of either or both of the weldswitches 304- accordingly. Otherwise the units travel the full length of the seam to be welded and until switches 136 are actuated by their stop 'blocks 131 to reverse Athe motor and cause return movement of the ing' units, hevactuates one or both of the Welding units lto initial position. After .the t Welding is completed, the operator turns valves 300 to exhaust air through ports 303 of. cylinders 120 and to cause air to pass throughl'pipes 306 to ports 307 of these cylinders, thusk causing the welding units to be moved away from the housing. The operatormay cause this movement at any time he so desires.

The jig and housing thereon are suitably grounded, Vas by conventional ground wires 308, attached to the frame 143 of the jig. Obviouslyfthe grounds may be established at other places, and either directly to the housing, or to the jig or to any desired part, so long as the ground established is conducive toproper and reliable welding by means of the apparatus `employed. The cir= cuit Wires to the welding heads are shown at 299. i

When it is desired to weld bearing tubes 163 Within the arms of the housings, it is` suggested a small sleeve 305 be placed on and y welded to the end 'of eaclitube and then the' tube and sleeve be secured in place on one housing section by slight spot welding.' The edges of housing sections may be cut out in;A

slightly over these sleeves, as at 308, which Y.

Will result in the welding wire,'as itI passes these points, establishing a large and-strong weld between the sleeves and the housing sections, thus securely fastening the tubes in accurate, aligned position within the housing arms.

' Preferably the edges of the housing are arranged to meet ina V, as at 809, which fills up with the welding flux, and thus a very strong weld is obtained. y This V-shaped seam, however is o tional.

, As before state whenever the welding arc becomes extinguished, the advancing of the welding head ceases, and as soon as the arc is restored the advance movement resumes. This may be accomplshed by placing the arc in the circuit which drives the motor 87, the circuit for reversing the motor, however, is not througlnthe arc.

Although the machine above described as illustrating one spec'fic embodiment of 'our invention hasbeen designed primarilyfor welding axle housings, it is readily apparent that machines adapted to operate on other articles may be built in accordance with and under our invent'on herein disclosed. 0bviously, many changes can be made in the construction and asthe invention can have many embodiments, apparently differing from each other in a wide degree, it, is to be understood that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as` illustrative and not in a limiting sense.l It is also to be undelstood that the invention is not limited to the specific features of con-` struction', arrangement of parts or combina tions f elements, shown or described, but that the scope of the invent'on is as broad as is indicated in the claims which follow.

l/Vhat we claim is 1. In a jig of the character described, in combination, a support for work of ,elongated shape, means, comprising a system of pneumatic work engaging devices engageable with said work toward its center an`d also at itsy ends and also at intermediate points, for placing and maintaining said work rigidly in predetermined/position on said jig, and 'a single control means for operating all of saidpwork engaging devicesn in predetermined sequence.

2. In a jig for an unwelded axle housing having a bowed-out central -portion and opposite arms and comprising two longitu. dinal complementary sections, and a bearing tube in each housing arm, plungers engageable within the inner and outer ends of said bearing tubes, when said housing is on the jig, whereby said tubes are-placed and held in accurate alignment.

3. In a jig for an unwelded axle housing having a bowed-out' central portion and opposite arms and comprising two longitudinal complementary sections, a pair of movable anvil blocks fitting within the bowed-out portion of the housing, when on the `ig, movablel wedges,`coacting with said blocs, and means for moving said wedges for expanding said blocks into firm engagement with' the adjacent portions of `the housing. L g

4.- In a jig for an unwelded axle housing having a" bow'edfout^ central portion and opposite arms and comprising two longi'- tudinal complementary sections, a pair of movable anvil blocks fitting within the bowed-out portion of the housing, when-0nthe jig, movable wedges, coacting with said bloiks, means for moving said wedges for expanding said blocks into firm engagement with the adjacent ortions of the' housing, and spring means or collapsing said blocks when released by said wedges.

5. In a jig for an unwelded axle housing having a bowed-out central portion. and opposite arms and comprising two longitudinal: (omplementary sections, a pair of anvil 'blocks fitting within the bowed-out portion of the housing, when on thejig, and expansible into firm Contact with the adjacent portions` thereof, a pair of bars 4secured to the jg and having opposite exterior guide surfaces coacting with said blocks, said bars havingl a mutual tapered surface abutment, and one of said bars being movable lon'fritudinally with respect to the other whereby the distance between saidl guide surfaces mayv be varied to accurately coact with said blocks.

46. In a jig for an unwelded axle housing having a bowed-outcentral portion and opposite arms and comprising two longitudinal complementary sections, .a pair of anvil blocks fitting within the bowed-out portion of the housing, when on the jig,E and ex-` -pansible into firm contact with' the adjacent portions thereof, a pair of bars secured to the jig'- and having opposite exterior guide surfai es coat-ing with said blocks, said bars havinga mutual tapered surface abutment, and one of said bars being movable longitudinallywith respect to the other whereby the distance between said guide surfaces llt) may bevaried to accurately coact with said means for moving said wedges for expand` i.

ing said blocks into firm engagement with 4 the adjacent portions of the housing, saidblocks having guide channels, and said wedges having; portions disposed infsaids channels and confined between'the walls posite arms and comprising two longitudinal complementary sections, and bearing tubes within the housing arms, anvil bloc-ks fitting within the bowed-out portion of the housing, when on the jig, movable wedges, coacting 10 with said blocks, plunger heads on said wedges eiigageable in the inner ends of said bearing tubes, and means for moving said wedges apart to expand saidsblocks into firm engagement with the adjacent portions of the housing and to engage said plunger heads in the inner ends of' said bearing tubes, whereby said housing portions and tube ends ai'e placed and held firmly in accurate alignment.

9. In a jig for an unwelded axle housing having a bowed-out cent 'al portion and opposite armsand comprising two longitudinal complementary sections, and bearing tubesV within the housing arms, anvil blocks fitting within the bowed-out portion of the housing,

when on the jig, movable wedges, coacting with said blocks, plunger heads on said wedges engageable in the inner ends of said bearing tubes, vmeans for moving said wedges apart to expand said blocks into firm engagement with the adjacent portions of the housing and to engage said plunger heads in the inner ends of said bearing tubes, whereby said housing portions and ltube ends are placed and held firmly in accuiate alignment, means engageable with the housing from the outside at its central portion for clamping the central portions of the housing sections firmly together and against said anvil blocks, means engageable with said hous- 40 ing arm portions for clamping said arm poi'- tions firmly together, and plungers engageable within the outer ends of the housing arms and bearing tubes to place and hold firmly said arm ends and tube ends in accu- ,45 rate alignment, andmeans for actuating each of said means.

l0. In a jig for an unwelded axle housing having a bowed-out central portion and opposite arms and comprising two' longitudinal complementary sections, and bearing tubes f within the housing arms, anvil blocks fitting,y f" within the bowed-out portion of the housing,

when on the jig, movable wedges, coaeting with said blocks, plunger heads on said wedges engageable in the Ainner ends of said bearing tubes, means for moving said wedges apart to expand said blocks into firm engagement with the adjacent portions of the housing and to engage said plunger heads in the inner ends of said bearing tubes, whereby said housing portions and tube ends are placed and held firmly in accu# rate alignmentV means engageable with the housing from the outside at its central portion for clamping the central portions of the housing` sections firmly together and against said anvil blocks, means engageable with said housing arm portions for clamping said arm portions firmly together, and plungers engageable within the outer ends of the housing arms and bearing tubes to place and hold firmly said arm ends and tube ends in accurate alignment, and means foractuating all of said means in predetermined sequence,

'said actuating means includingpneumatic within the bowed-out portion of the housing, Y i

when on the jig, movable wedges, coacting with said blocks, plunger heads on said wedges cngageable in the inner ends of said bearing tubes, means for moving said wedges apart to expand said blocks into firm engagement wit-h the adjacent portions of the housing and to engage said plunger heads` in the inner ends of said bearing tubes, whereby said housing portions and tube ends are placed and held firmly in accurate alignnient, means engageable with the housing from the outside at Aits central portion for clainj'iing the central portions of the housing sections firmly together and against said anvil blocks, means engageahle with said housing arm portions for clamping said arm portions firmly together, antl plungers engageable within the Outer ends of the housing arms and bearing tubes to place and hold firmly said arm ends and tube ends in accurate alignment, means for actuating all of said means in predetermined sequence, said actuating means including pneumatic cylinders, double-acting pistons within said cylinders, a valve` air pipes connecting said valve with said cylinders on both sides of the pistons, a source of air supply leading to said valve, exhaust outlets from said valve, a. valve cone, and a single operating handle for rotating said cone, said cone having passages `and closure walls coacting with the valve ports in predetermined sequence,

This specification signed this 10th day of September, 1925.

VALTER. H. DIARDENNE. J. OLIN LANDIS. LEWIS H. CHRISTENSEN. 

